P1099: A PHASE II, MULTICENTER, SINGLE-ARM STUDY OF PARSACLISIB, A PI3KΔ INHIBITOR, IN RELAPSED OR REFRACTORY FOLLICULAR LYMPHOMA IN CHINA: UPDATED RESULTS FROM THE STUDY
Authors: Zhong Zheng, Huilai Zhang, Keshu Zhou, Hui Zhou, LI Zhang, Caixia LI, Min Zhou, Wenbin Qian, Zhiming LI, Qingyuan Zhang, Ying Cheng, Liu Peng, Zhenyu LI, Liping Su, Fei LI, Xiuhua Sun, Jingwen Wang, Yuhuan Gao, Xielan Zhao, Kunyan LI, Kaiyang Ding, Zunmin Zhu, Ying Wang, Hongmei Jing, Xiaohong Xu, Xin Wang, Zimin Sun, Da Gao, Wei-LI Zhao
Journal: HemaSphere (2023)

Topic: 18. Indolent and mantle-cell non-Hodgkin lymphoma - Clinical Background: For patients (pts) with follicular lymphoma (FL) in line 3 or higher, treatment options are limited. Parsaclisib is a potent, highly-selective, next-generation PI3Kδ inhibitor. Data from previous data cutoffs (primary: Apr 2021; initial update: Dec 2021) showed that parsaclisib demonstrated promising efficacy, and an acceptable safety profile in line 3 or higher FL pts in China. Here, we report updated results from the multicenter, open-label Phase 2 study. Aims: This Phase 2 study is designed to evaluate the safety, tolerability and efficacy of parsaclisib in pts with line 3 or higher Chinese follicular lymphoma. Methods: Key eligibility included, age ≥ 18 years, histologically confirmed FL grade 1, 2, or 3a, ≥ 2 prior systemic therapies, ECOG PS ≤ 2, and ineligible for hematopoietic stem cell transplantation (HSCT). Pts received parsaclisib 20 mg once daily (QD) for 8 weeks followed by 2.5 mg QD, until disease progression (PD), unacceptable toxicity, death or withdrawal of consent. Prophylaxis for Pneumocystis jirovecii pneumonia (PJP) was required. The primary endpoint was objective response rate (ORR) as assessed by an independent review committee (IRC) according to the Lugano 2014 criteria, secondary endpoints included investigator-assessed ORR according to the Lugano 2014 criteria, duration of response (DoR), PFS, OS, and safety and tolerability. Results: At the data cutoff date (Dec 31, 2022), 61 pts (median age: 50 years; male [n=35, 57.4%]) were enrolled. Thirty-one pts remained on treatment and 30 pts had discontinued study treatment mainly due to PD (n = 21). All 61 pts were evaluated for response by the investigator according to the Lugano 2014 criteria. With a median follow-up time of 22.1 months (range 18.7-32.3), the ORR and complete response rate (CRR) were 90.2% (n=55, 95% CI: 82.7-97.6) and 37.7% (n=23, 95% CI: 25.5-49.9), respectively. Median DOR and PFS were 20.4 months (95% CI: 17.4-NC) and 22.1 months (95% CI: 16.8-NC), respectively. Median OS was not achieved, and the 24-month OS rate was 91.5% (95% CI: 80.7-96.4). All 61 pts were included in the safety analysis. The overall safety profile was consistent with previous reports and no new safety signals were identified. Summary/Conclusion: With longer follow-up, parsaclisib demonstrated a high rate of complete response and durable responses, and had an acceptable safety profile. These results demonstrate that parsaclisib has a favorable benefit-risk profile in patients with line 3 or higher Chinese follicular lymphoma. Clinical trial information: NCT04298879 Keywords: Targeted therapy, Follicular lymphoma, Phase II